Flexural layered deformational model of reinforced concrete members

摘要

Based on a method recently proposed by the author and his co-workers, new average-stress/average-strain relations of cracked tensile concrete have been derived from experimental moment-curvature diagrams of under-reinforced concrete beams reported in the literature. Using these and previously obtained relations, a new constitutive relationship of cracked tensile concrete has been proposed for short-term deformational analysis of flexural reinforced concrete members. The stress-strain relationship, called the Flexural, accumulates tension-softening and tension-stiffening effects. A quantitative dependence has been established between the length of the descending branch and the reinforcement ratio. The Flexural constitutive relationship has been applied in a simple engineering technique based on a layered approach and the principles of strength of materials. To assess the accuracy of the technique, deflections/curvatures have been calculated for a large number of experimental reinforced concrete beams reported in the literature. Comparison has been carried out with well-known constitutive relationships and design code methods such as the ACI, EC2 and SNiP (Russian code).